U.S. patent number 11,255,672 [Application Number 16/665,971] was granted by the patent office on 2022-02-22 for system having an extended life high performance sensor.
This patent grant is currently assigned to Honeywell International Inc.. The grantee listed for this patent is Honeywell International Inc.. Invention is credited to Dean Eivind Johnson, Alan Bruce Touchberry.
United States Patent |
11,255,672 |
Touchberry , et al. |
February 22, 2022 |
System having an extended life high performance sensor
Abstract
A system that includes a high performance sensor to provide
accurate measurements and at least one dissimilar sensor that is
less accurate. The at least one dissimilar sensor is of a different
type of sensor than the high performance sensor while providing a
same type of measurement as the high performance sensor. The at
least one dissimilar sensor has a longer life expectancy than the
high performance sensor. An at least one controller is configured
to start both the high performance sensor and the at least one
dissimilar sensor at startup of the system, to turn off the high
performance sensor after a select period of time, and to output
measurement data based on measurements of the high performance
sensor while the high performance sensor is on and output the
measurement data based on the at least one dissimilar sensor when
the high performance sensor is off.
Inventors: |
Touchberry; Alan Bruce (Saint
Louis Park, MN), Johnson; Dean Eivind (Orono, MN) |
Applicant: |
Name |
City |
State |
Country |
Type |
Honeywell International Inc. |
Morris Plains |
NJ |
US |
|
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Assignee: |
Honeywell International Inc.
(Charlotte, NC)
|
Family
ID: |
72717677 |
Appl.
No.: |
16/665,971 |
Filed: |
October 28, 2019 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20210123738 A1 |
Apr 29, 2021 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01C
19/662 (20130101); G01C 19/5776 (20130101); G01C
19/66 (20130101); G01P 21/00 (20130101); G01C
25/005 (20130101); G01P 3/00 (20130101) |
Current International
Class: |
G01P
3/00 (20060101); G01C 19/66 (20060101); G01P
21/00 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2685212 |
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Jan 2014 |
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EP |
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2016107806 |
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Jul 2016 |
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WO |
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Other References
European Patent Office, "Extended European Search Report from EP
Application No. 20199485.2", from Foreign Counterpart to U.S. Appl.
No. 16/665,971, filed Mar. 18, 2021, pp. 1 through 9, Published:
EP. cited by applicant.
|
Primary Examiner: Nur; Abdullahi
Attorney, Agent or Firm: Fogg & Powers LLC
Claims
The invention claimed is:
1. A system comprising: a high performance sensor to provide
accurate measurements; at least one dissimilar sensor, the at least
one dissimilar sensor being of a different type of sensor than the
high performance sensor while providing a same type of measurement
as the high performance sensor, the at least one dissimilar sensor
being less accurate than the high performance sensor and having a
longer life expectancy than the high performance sensor; and at
least one controller in communication with the high performance
sensor and the at least one dissimilar sensor, the at least one
controller configured to start both the high performance sensor and
the at least one dissimilar sensor at startup of the system, the at
least one controller further configured to turn off the high
performance sensor after a select period of time, the at least one
controller further configured to output measurement data based on
measurements of the high performance sensor while the high
performance sensor is on and output the measurement data based on
the at least one dissimilar sensor when the high performance sensor
is off.
2. The system of claim 1, wherein the high performance sensor has a
life expectancy that is less than at least one of a life expectancy
of the at least one dissimilar sensor and a mission of a vehicle
implementing the high performance senor.
3. The system of claim 1, wherein in the high performance sensor is
a ring laser gyroscope (RLG) and the measurements are rate/angle
measurements.
4. The system of claim 3, wherein the at least one controller is
further configured to determine bias errors between the rate/angle
measurements of the RLG and the rate/angle measurements of the at
least one dissimilar sensor when the RLG is on and convert
rate/angle measurements of the at least one dissimilar sensor using
the determined bias errors when the RLG is turned off.
5. The system of claim 4, further comprising: at least one Kalman
filter used by the at least one controller to determine the bias
error, the at least one controller is configured to use an
estimated solution from the Kalman filter when the RLG is turned
off and use the estimated solution to calibrate outputs of the at
least one dissimilar sensor.
6. The system of claim 5, further comprising: a memory to store
calibration information based on the determined bias errors, the at
least one controller in communication with the memory.
7. The system of claim 6, wherein the at least one controller is
further configured to turn on the RLG periodically to update
calibration information.
8. The system of claim 1, further comprising: a clock, the at least
one controller in communication with the clock to track how long
the high performance sensor is on.
9. The system of claim 1, wherein the select period of time is the
time needed to overcome run-to-run repeatability issues of the at
least one dissimilar sensor.
10. A gyroscope system comprising: a ring laser gyroscope (RLG) to
provide rate/angle measurements; a plurality of dissimilar sensors,
each dissimilar sensor being of a different type of sensor than the
RLG that also provides rate/angle measurements; and at least one
controller in communication with the RLG and the plurality
dissimilar sensors, the at least one controller configured to start
both the RLG and the plurality of dissimilar sensors at startup of
the gyroscope system, the at least one controller further
configured to turn off the RLG after a select period of time, the
at least one controller further configured to output rate/angle
measurements based on the RLG while the RLG is on and output
rate/range data based on the plurality of dissimilar sensor when
the RLG is turned off, the at least one controller is further
configured to determine bias errors between an output of the RLG
and the plurality of dissimilar sensors when the RLG is on and
calibrate rate/angle measurements from the plurality of dissimilar
sensors based on the determined bias errors when the RLG is turned
off.
11. The gyroscope system of claim 10, further comprising: a memory
to store calibration information based on the bias error
determinations, the at least one controller in communication with
the memory.
12. The gyroscope system of claim 10, further comprising: a clock,
the at least one controller in communication with the clock, the at
least one controller configure to track how long the RLG is on.
13. The gyroscope system of claim 10, wherein the select period of
time is the time needed to overcome run-to-run repeatability issues
of the at least one dissimilar sensor.
14. The gyroscope system of claim 10, wherein the RLG is a RLG
triad and each dissimilar sensor is a dissimilar sensor triad.
15. A method of operating a gyroscope system, the method
comprising: turning on a ring laser gyroscope (RLG) and at least
one dissimilar sensor, each dissimilar sensor being of a different
type of sensor than the RLG that also provides rate/angle
measurements; using the rate/angle measurements of the RLG when the
RLG is on; determining bias errors associated with the rate/angle
measurements of the at least one dissimilar sensor; storing
calibration information based on the bias errors in an memory;
turning off the RLG; and calibrating the rate/angle measurements
from the at least one dissimilar sensor based on the stored
calibration information.
16. The method of claim 15, further comprising: applying a Kalman
filter in determining the bias errors of the rate/angle
measurements of the at least one dissimilar sensor.
17. The method of claim 16, wherein the Kalman filter uses
rate/angle measurements from the RLG and the at least one
dissimilar sensor in determining bias errors.
18. The method of claim 15, wherein turning off the RLG further
comprises: turning off the RLG after a select time has passed
needed to overcome run-to-run repeatability issues of the at least
one dissimilar sensor.
19. The method of claim 15, further comprising: turning the RLG
back on to update the calibration information.
20. The method of claim 15, wherein the RLG is a RLG triad and the
at least one dissimilar sensor is at least one dissimilar sensor
triad.
Description
BACKGROUND
A gyroscope may be used as a navigational aid. Gyroscopes measure
orientation and angular velocity. In an aircraft application, these
measurements provide vital information used to safely operate the
aircraft as it traverses through its travel path. There are several
different types of gyroscopes that are used for aircraft
navigation. Two example types include a ring laser gyroscope (RLG)
and a microelectromechanical system (MEMS) gyroscope. A RLG has
excellent run-to-run stability but its life expectancy is less than
the life expectancy of an aircraft. Other types of sensors, such as
MEMS gyroscopes, have a good angle random walk (ARW) and good
in-run bias stability but poorer run-to-run stability. ARW is a
velocity error build up over time due to noise. An in-run bias
stability is a measure of a random variation in bias computed over
a specified sample time and averaging time interval. A run-to-run
(or the turn-on to turn-on) stability is a residual output error
that occurs after calibration and internal compensation that is
caused by at least the effects of turn-ons, turn-offs, time and
temperature variations. Currently a suitable very long life
self-aligning gyroscope system can therefore not be made by either
technology type.
SUMMARY
The following summary is made by way of example and not by way of
limitation. It is merely provided to aid the reader in
understanding some of the aspects of the subject matter described.
Embodiments provide a system that selectively incorporates a high
performance sensor and at least one dissimilar sensors at select
times during operation of the system to extend the life of the high
performance sensor.
In one embodiment, a system that includes a high performance
sensor, at least one dissimilar sensor and at least one controller
is provided. The high performance sensor is used to provide
accurate measurements. The at least one dissimilar sensor is of a
different type of sensor than the high performance sensor while
providing a same type of measurement as the high performance
sensor. The at least one dissimilar sensor is less accurate than
the high performance sensor and has a longer life expectancy than
the high performance sensor. The at least one controller is in
communication with the high performance sensor and the at least one
dissimilar sensor. The at least one controller is configured to
start both the high performance sensor and the at least one
dissimilar sensor at startup of the system. The at least one
controller is further configured to turn off the high performance
sensor after a select period of time. The at least one controller
is further configured to output measurement data based on
measurements of the high performance sensor while the high
performance sensor is on and output the measurement data based on
the at least one dissimilar sensor when the high performance sensor
is off.
In another example embodiment, another gyroscope system including a
ring laser gyroscope (RLG) to provide rate/angle measurements, a
plurality of dissimilar sensors and at least one controller is
provided. Each dissimilar sensor is of a different type of sensor
than the RLG that also provides rate/angle measurements. The at
least one controller is in communication with the RLG and the
plurality dissimilar sensors. The at least one controller is
configured to start both the RLG and the plurality of dissimilar
sensors at startup of the gyroscope system. The at least one
controller is further configured to turn off the RLG after a select
period of time. The at least one controller is further configured
to output rate/angle measurements based on the RLG while the RLG is
on and output rate/range data based on the plurality of dissimilar
sensor when the RLG is turned off. The at least one controller is
further configured to determine bias errors between an output of
the RLG and the plurality of dissimilar sensors when the RLG is on
and calibrate rate/rage data from the plurality of dissimilar
sensors based on the determined bias errors when the RLG is turned
off.
In yet another embodiment, a method of operating a gyroscope system
is provided. The method includes turning on a ring laser gyroscope
(RLG) and at least one dissimilar sensor, each dissimilar sensor
being of a different type of sensor than the RLG that also provides
rate/angle measurements; using the rate/angle measurements of the
RLG when the RLG is on; determining bias errors associated with
rate/angle measurements of the at least one dissimilar sensor;
storing calibration information based on the bias errors in an
memory; turning off the RLG; and calibrating the rate/angle
measurements from the at least one dissimilar sensor based on the
stored calibration information.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments can be more easily understood and further advantages
and uses thereof will be more readily apparent, when considered in
view of the detailed description and the following figures in
which:
FIG. 1 is a block diagram of a gyroscope system according to one
exemplary embodiment;
FIG. 2 illustrates an operational gyroscope system flow diagram
according to one exemplary embodiment;
FIG. 3 illustrates a timing flow diagram according to one exemplary
embodiment;
FIG. 4 illustrates a solution determination flow diagram according
to one exemplary embodiment;
FIG. 5 is a block diagram of another gyroscope system according to
one exemplary embodiment; and
FIG. 6 illustrates an operational triad gyroscope system flow
diagram according to one exemplary embodiment;
In accordance with common practice, the various described features
are not drawn to scale but are drawn to emphasize specific features
relevant to the subject matter described. Reference characters
denote like elements throughout Figures and text.
DETAILED DESCRIPTION
In the following detailed description, reference is made to the
accompanying drawings, which form a part hereof, and in which is
shown by way of illustration specific embodiments in which the
inventions may be practiced. These embodiments are described in
sufficient detail to enable those skilled in the art to practice
the embodiments, and it is to be understood that other embodiments
may be utilized and that changes may be made without departing from
the spirit and scope of the present invention. The following
detailed description is, therefore, not to be taken in a limiting
sense, and the scope of the present invention is defined only by
the claims and equivalents thereof.
Embodiments provide a system that improves the life expectancy of a
high performance sensor. Systems described herein include the high
performance sensor and at least one dissimilar sensor. The at least
one dissimilar sensor provides the same type of measurements as the
high performance sensor but is typically not as accurate as the
high performance sensor. Further, the at least one dissimilar
sensor may have a longer life expectancy than the high performance
sensor. The life expectancy of the high performance sensor is
extended in embodiments by selectively turning off the high
performance sensor during periods of a vehicle mission where
measurements from the at least one dissimilar sensor can be safely
used. Vehicle applications in which the system may be incorporated
in, include but are not limited to, cars, trucks, boats, aircraft,
spacecraft etc. Systems described herein may be applied in vehicles
where the vehicles mission is longer than the life expectancy of
the high performance sensor or where the vehicle has a longer life
expectancy than the high performance sensor.
Embodiments are describe hereafter as applying to the example
embodiment of a gyroscope system that selectively incorporates a
ring laser gyroscope (RLG) (an example high performance sensor) and
at least one other dissimilar sensor, such as but not limited to, a
microelectromechanical system (MEMS) gyroscope at select times to
extend the life of the RLG. In particular, in some embodiments, the
gyroscope system only uses the accurate sensor (RLG) long enough to
overcome the run-to-run repeatability issues of the other
dissimilar sensors. The RLG is then shut off to limit the amount of
time the RLG is used. The gyroscope system is just one example of a
system that may implemented. Any system that requires a high
performance sensor whose expected life is less than the expected
life of an associated vehicle or has an expected life less than a
vehicle mission may implement systems described herein. Hence,
embodiments are not just limited to gyroscope systems.
Referring to FIG. 1, a block diagram of gyroscope system 100 of one
example is illustrated. The gyroscope system 100 is illustrated as
including a controller 102, a memory 110, a RLG 104 (high
performance sensor), a plurality of dissimilar sensors 106-1
through 106-N, a Kalman filter 112, a vehicle control 114 and a
clock 116. The dissimilar sensors 106-1 through 106-N may be other
types of gyroscopes, such as MEMS gyroscopes, or other devices that
provide orientation and angular velocity information. The vehicle
control 114 may be a vehicle system that uses the measurements,
generally described as rate/angle measurements, from the gyroscope
system 100 to at least display or even control aspects of the
vehicle based on the rate/angle measurements from the gyroscope
system 100 for navigation reasons. The clock 116 is used by the
controller 102 to at least track the time the RLG 104 is on in one
example embodiment.
In general, the controller 102 may include any one or more of a
processor, microprocessor, a digital signal processor (DSP), an
application specific integrated circuit (ASIC), a field program
gate array (FPGA), or equivalent discrete or integrated logic
circuitry. In some example embodiments, controller 102 may include
multiple components, such as any combination of one or more
microprocessors, one or more controllers, one or more DSPs, one or
more ASICs, one or more FPGAs, as well as other discrete or
integrated logic circuitry. The functions attributed to the
controller 102 herein may be embodied as software, firmware,
hardware or any combination thereof. The controller may be part of
a system controller or a component controller. The memory 110 may
include computer-readable operating instructions that, when
executed by the controller provides functions of the gyroscope
system 100. Such functions may include the functions of turning on
and off the RLG 104 as described below. The computer readable
instructions may be encoded within the memory 110. Memory 110 may
comprise computer readable storage media including any volatile,
nonvolatile, magnetic, optical, or electrical media, such as, but
not limited to, a random access memory (RAM), read-only memory
(ROM), non-volatile RAM (NVRAM), electrically-erasable programmable
ROM (EEPROM), flash memory, or any other storage medium.
FIG. 2 illustrates an operational gyroscope system flow diagram 200
of an example embodiment. The flow diagram 200 is provided as a
series of sequential blocks. The order and even the content may be
different in other embodiments. Hence embodiments are not limited
the sequence and content illustrated in the example flow diagram of
FIG. 2.
The process starts in the operational gyroscope system flow diagram
200 by turning on all of the sensor devices at block (202). All the
sensors devices include the RLG 104 and the dissimilar sensors
generally indicated as 106. The controller 102 then receives all
the sensor or measurement data that includes the rate/angle
measurements, in the gyroscope system embodiment, from the RLG 104
and the dissimilar sensors 106. The controller 102, based on
instructions stored in the memory 110, uses the rate/angle
measurements of the RLG data as primary measurement data at block
(210) while the RLG 104 is on.
Further, a bias error for N dissimilar sensors is computed at block
(206) by the controller 102. A compensation model based on the bias
error for each dissimilar sensor 106 is loaded on and stored in the
memory 110 at block (208) in this example embodiment. In one
embodiment the compensation model is based on a comparison of
measurement outputs of the dissimilar sensors 106 with measurement
outputs of the RLG 104. At block (212), the controller 102 converts
to using the dissimilar sensor measurement outputs for rate
measurements using the compensation module stored in the memory
110. The RLG 104 is then shut off at block (214).
An example of a timing flow diagram 300 of an example embodiment is
illustrated in FIG. 3. The flow diagram 300 is provided as a series
of sequential blocks. The order and even the content may be
different in other embodiments. Hence embodiments are not limited
the sequence and content illustrated in the example flow diagram of
FIG. 3.
In this example embodiment, both the RLG 104 and the dissimilar
sensors are turned on at block (302). The time the RLG is on is
tracked at block (304). Once it is determined at block (306) that
the select time is reached, the RLG 104 is turned off at block
(308). In one embodiment the time period is a period that is long
enough to overcome the run-to-run repeatability issues of the
dissimilar sensors 106.
In one embodiment both the dissimilar sensors 106 and RLG 104 are
turned on at the start of a "day." Upon start up the RLG 104
self-aligns and provides data to calibrate the dissimilar sensors
biases to .about.0.002 to 0.003 deg/hr for a select initial
calibration period of time. For example the select period of time
may be a first hour of operation. The RLG 104 is then shut off and
the dissimilar sensors 106 is used to navigate for the rest of the
"day." Using this system, for a 15-hour day, the RLG 104 useful
life may be extended by 15.times.. This system not only addresses
dissimilar sensor run-by-run bias repeatability issues (such as
MEMS run-by-run bias repeatability issues), it extends the life the
RLG 104.
In an example embodiment, a Kalman filter 112 may be used during
the select calibration period of RLG operation to determine the
bias error of the dissimilar sensors 106. After that time,
calibrated (adjusted) rate/angle measurements from the dissimilar
sensors 106 based on the determined bias errors is used for the
remainder of the "day" and shut the RLG 112 is shut off.
Further in embodiments, the RLG 104 may be turned on at any time
for a period of time to provide a fresh solution (update
calibration information) to add fault tolerance or detection to the
gyroscope system 100. This is further illustrated in the timing
flow diagram of FIG. 3. At block (310) it is determined if a new
solution at block (310) is needed. In an embodiment, the need for a
new solution is a need for a new compensation model (or calibration
information) stored in memory 110 as described above in FIG. 2. If
a new solution is needed, the RLG 104 is turned on at block (312).
The time the RLG 104 is on is tracked at block (314). Once it is
determined at block (316) that a select time is reached, the RLG
104 is turned off. The operating time of the RLG 104 may be
variable depending upon the ARW of the RLG 104 and the level of
bias uncertainty needed for the dissimilar sensors.
An example of an application of the Kalman filter is illustrated in
a solution determination flow diagram 400 of FIG. 4. The flow
diagram 400 is provided as a series of sequential blocks. The order
and even the content may be different in other embodiments. Hence
embodiments are not limited the sequence and content illustrated in
the example flow diagram of FIG. 4.
The process starts a block (402) where it is determined if the RLG
104 is on. If it is on, the process uses the Kalman filter 112 at
block (404) to determine bias error associated with the dissimilar
sensor measurements. Calibration information that is based on the
determined bias errors is stored the memory 110 at block (406). If
the RLG is not on as determined by block (402), the stored
calibration information is used in generating rate/angle
measurements from the dissimilar sensor(s) at block (408).
Embodiments may also be applied to sensor triads as illustrated in
FIG. 5. The sensor triad gyroscope system 500 example of FIG. 5.
This gyroscope system 500 is illustrated as including a RLG triad
504, a plurality of dissimilar sensor triads 106-1 through 106-N
Kalman, a filter 512, a vehicle control 514 and a clock 516. The
dissimilar sensor triads maybe other types of gyroscope triads
including MEMS triads that provide orientation and angular velocity
information. Similar to the embodiment of FIG. 1, this embodiment
includes a controller 502 and a memory 510 to perform at least the
functions described above regarding the embodiment described in the
FIG. 1.
FIG. 6 illustrates an operational triad gyroscope system flow
diagram 600 of an example embodiment. The flow diagram 600 is
provided as a series of sequential blocks. The order and even the
content may be different in other embodiments. Hence embodiments
are not limited the sequence and content illustrated in the example
flow diagram of FIG. 2.
The process starts in the operational gyroscope system flow diagram
600 by turning on all of the sensor devices at block (602). All the
sensors devices include the RLG triad 504 and the dissimilar
sensors triads generally indicated as 506. The controller 502 then
receives all the sensor data that includes rate/angle measurements
from the triad RLG 504 and the dissimilar sensor triads 506. The
controller 502 at block (604), based on instructions stored in the
memory 510, the controller 502 uses the RLG data as primary data at
block (610) while the RLG 504 is on.
The controller 502 at block (606) computes a bias error for N
dissimilar sensor triads. The bias error for N dissimilar sensor
triads is stored in the memory at block (608). As described above,
in an embodiment calibration information based on the bias error is
stored in the memory. At block (612) data from the N dissimilar
sensor triads 506 is converted for use using the computed bias
error. The RLG Triad is then shut off at block (614). The converted
measurements from the N dissimilar sensor triads 506 are then used
by the gyroscope system 500 while the RLG triad 504 is turned
off.
EXAMPLE EMBODIMENTS
Example 1 is a system that includes a high performance sensor, at
least one dissimilar sensor and at least one controller. The high
performance sensor is used to provide accurate measurements. The at
least one dissimilar sensor is of a different type of sensor than
the high performance sensor while providing a same type of
measurement as the high performance sensor. The at least one
dissimilar sensor is less accurate than the high performance and
has a longer life expectancy than the high performance sensor. The
at least one controller is in communication with the high
performance sensor and the at least one dissimilar sensor. The at
least one controller is configured to start both the high
performance sensor and the at least one dissimilar sensor at
startup of the system. The at least one controller is further
configured to turn off the high performance sensor after a select
period of time. The at least one controller is further configured
to output measurement data based on measurements of the high
performance sensor while the high performance sensor is on and
output the measurement data based on the at least one dissimilar
sensor when the high performance sensor is off.
Example 2 includes the system of Example 1, wherein the high
performance sensor has a life expectancy that is less than at least
one of a life expectancy of the at least one dissimilar sensor and
a mission of a vehicle implementing the high performance senor.
Example 3 includes the system of any of the Examples wherein in the
high performance sensor is a ring laser gyroscope (RLG) and the
measurements are rate/angle measurements.
Example 4 includes the system of Example 3, wherein the at least
one controller is further configured to determine bias errors
between the rate/angle measurements of the RLG and the rate/angle
measurements of the at least one dissimilar sensor when the RLG is
on and convert rate/angle measurements of the at least one
dissimilar sensor using the determined bias errors when the RLG is
turned off.
Example 5 includes system of Example 4, further including at least
one Kalman filter used by the at least one controller to determine
the bias error, the at least one controller is configured to use an
estimated solution from the Kalman filter when the RLG is turned
off and use the estimated solution to calibrate outputs of the at
least one dissimilar sensor.
Example 6 includes the system of Example 5, further including a
memory to store calibration information based on the determined
bias errors, the at least one controller in communication with the
memory.
Example 7 includes the system of Example 6, wherein the at least
one controller is further configured to turn on the RLG
periodically to update calibration information.
Example 8 includes the system of the Examples 1-7, further
including a clock. The at least one controller is in communication
with the clock to track how long the high performance sensor is
on.
Example 9 includes the system of any of the Examples 1-8, wherein
the select period of time is the time needed to overcome run-to-run
repeatability issues of the at least one dissimilar sensor.
Example 10 is a gyroscope system including a ring laser gyroscope
(RLG) to provide rate/angle date, a plurality of dissimilar sensors
and at least one controller. Each dissimilar sensor is of a
different type of sensor than the RLG that also provides rate/angle
measurements. The at least one controller is in communication with
the RLG and the plurality dissimilar sensors. The at least one
controller is configured to start both the RLG and the plurality of
dissimilar sensors at startup of the gyroscope system. The at least
one controller is further configured to turn off the RLG after a
select period of time. The at least one controller is further
configured to output rate/angle measurements based on the RLG while
the RLG is on and output rate/range data based on the plurality of
dissimilar sensor when the RLG is turned off. The at least one
controller is further configured to determine bias errors between
an output of the RLG and the plurality of dissimilar sensors when
the RLG is on and calibrate rate/rage data from the plurality of
dissimilar sensors based on the determined bias errors when the RLG
is turned off.
Example 11 includes the gyroscope system of Example 10, further
including a memory to store calibration information based on the
bias error determinations. The at least one controller is in
communication with the memory.
Example 12 includes the gyroscope system of any of the Examples
10-11, further including a clock. The at least one controller in
communication with the clock. The at least one controller is
configure to track how long the RLG is on.
Example 13 includes the gyroscope system of any of the Examples
10-12, wherein the select period of time is the time needed to
overcome run-to-run repeatability issues of the at least one
dissimilar sensor.
Example 14 includes the gyroscope system of any of the Examples
10-13, wherein the RLG is a RLG triad and each dissimilar sensor is
a dissimilar sensor triad.
Example 15 is a method of operating a gyroscope system. The method
includes turning on a ring laser gyroscope (RLG) and at least one
dissimilar sensor, each dissimilar sensor being of a different type
of sensor than the RLG that also provides rate/angle measurements;
using the rate/angle measurements of the RLG when the RLG is on;
determining bias errors associated with rate/angle measurements of
the at least one dissimilar sensor; storing calibration information
based on the bias errors in an memory; turning off the RLG; and
calibrating the rate/angle measurements from the at least one
dissimilar sensor based on the stored calibration information.
Example 16 includes the method of Example 15, further including
applying a Kalman filter in determining the bias errors associated
with the rate/angle measurements of the at least one dissimilar
sensor.
Example 17 includes the method of Examples 16, wherein the Kalman
filter uses rate/angle measurements from the RLG and the at least
one dissimilar sensor in determining bias errors.
Example 18 includes the method of any of the Examples 15-17,
wherein turning off the RLG further includes turning off the RLG
after a select time has passed needed to overcome run-to-run
repeatability issues of the at least one dissimilar sensor.
Example 19 includes the method of any of the Examples 15-18,
further including turning the RLG back on to update the calibration
information.
Example 20 includes the method of any of the Examples 15-19,
wherein the RLG is a RLG triad and the at least one dissimilar
sensor is at least one dissimilar sensor triad.
Although specific embodiments have been illustrated and described
herein, it will be appreciated by those of ordinary skill in the
art that any arrangement, which is calculated to achieve the same
purpose, may be substituted for the specific embodiment shown. This
application is intended to cover any adaptations or variations of
the present invention. Therefore, it is manifestly intended that
this invention be limited only by the claims and the equivalents
thereof.
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